RU173095U1 - BUILT-IN MIXING HEAT EXCHANGER - Google Patents

Abstract

The proposed utility model relates to chemical engineering, namely, to designs of mixing heat exchangers built into reactors with two or more series-connected reaction zones, and can be used in chemical, petrochemical, fuel and energy, and other industries. The mixing heat exchanger built into the chemical reactor contains an outer pipe and an inner pipe installed coaxially with the formation of the annulus, the upper part of the outer pipe is closed and the upper part of the inner pipe is open, while the lower part of each pipe is fixed to a support plate designed for connection with the reactor vessel, in addition, at least one connecting pipe passes through the lower part of the outer pipe and the lower part of the inner pipe, which is used to supply a gaseous reaction mixture from the reactor volume to the space of the inner pipe, bypassing the annular space, while at least one of the nozzles has a spray device that atomizes the inner space of the inner pipe, the support plate contains holes for the exit of the cooled gas from the annulus .

Description

FIELD OF TECHNOLOGY

The proposed utility model relates to chemical engineering, namely, to designs of mixing heat exchangers built into reactors containing at least two reaction zones, and can be used in chemical, petrochemical, fuel and energy, and other industries. By reaction zone is meant an isolated volume bounded by a surface; if necessary, the reaction zone may be filled with catalyst.

BACKGROUND

For thermal stabilization of reactors, the reaction volume is divided into several parts, between which heat exchange devices are installed.

So in the patent for utility model RU 44066 U1 “Methanol synthesis reactor” (publ. 02.27.2005, IPC B01J 8/08, Togliattiazot OJSC) heat exchangers (tubular heat exchangers and tubular boilers) are placed between the reaction zones formed in the catalyst baskets . This ensures the removal of heat generated during the synthesis of methanol. The disadvantage of this solution is that the described heat exchange devices are difficult to manufacture and metal-intensive.

In some cases, a similar effect on cooling the gas mixture can be achieved by feeding reaction zones, the so-called Quenches. The latter are an inert gas / liquid or additional components of the reaction mixture. The most effective are mixing heat exchangers, in which the evaporation of the added component proceeds.

DISCLOSURE OF A USEFUL MODEL

The proposed built-in mixing heat exchanger (hereinafter referred to as ST) is designed to effectively reduce the temperature of the gaseous reaction mixture while reducing the mechanical stress of the ST structure caused by the temperature gradient inside it. The result is achieved due to the new design of CT, made with the possibility of adding to the raw material additional components of the reaction mixture or inert / slightly reactive components, including those entering the reactor in the form of liquids or supercritical fluids, in order to change the temperature of the reaction mixture. An additional effect of the application is the complete homogenization of the reaction mixture and additionally supplied components.

The result is achieved due to the following design features:

- fixing the heat exchanger pipes from only one end avoids damage and stresses in the material caused by repeated periodic changes in the size of metal parts during heating / cooling;

- the zone of intense evaporation / sublimation of the component added to the reaction mixture is located in the inner tube of the heat exchanger, which does not directly touch the surface bounding the reaction volume. This prevents the occurrence of mechanical stresses due to local cooling of the metal structure of the reactor, and avoids local cooling in the reaction layer;

- the proposed built-in design of the heat exchanger avoids the use of bulky external heat exchangers that require the removal of the gas mixture from the reactor for cooling, as well as the use of complex construction and expensive built-in tubular heat exchangers;

- in the case of embedding the heat exchanger in multi-shelf reactors, it is possible to use the inter-shelf space for heat exchange and gas homogenization.

The mixing heat exchanger built into the chemical reactor contains an outer pipe and an inner pipe installed coaxially with the formation of the annulus, the upper part of the outer pipe is closed and the upper part of the inner pipe is open, while the lower part of each pipe is mounted on a support plate designed for connection with the reactor vessel, in addition, at least one connecting pipe passes through the lower part of the outer pipe and the lower part of the inner pipe, which is used to supply a gaseous reaction mixture from the reactor volume to the space of the inner pipe, bypassing the annular space, while at least one of the nozzles has a spray device that atomizes the inner space of the inner pipe, the support plate contains holes for the exit of the cooled gas from the annulus .

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 shows a longitudinal section CT and a transverse section along the line aa. In FIG. 2 shows a longitudinal section of a CT in three-dimensional projection. In FIG. 3 shows schematically the movement of flows during the operation of the CT. In FIG. Figure 4 shows an enlarged image of the external and internal pipes of the CT and schematically shows the movement of flows along them during the operation of the CT.

In FIG. 5 shows a longitudinal section of a CT, in which a venturi is used as the inner pipe.

IMPLEMENTATION OF A USEFUL MODEL

The construction of the CT in the main embodiment is shown in FIG. 1. The design contains the outer 4 and inner 5 pipes ST, which are installed coaxially, forming the annular space 13. The lower parts of the pipes 4 and 5 are mounted on a support plate 9 connected to the reactor vessel 1. The outer pipe 4 is closed from the upper end, the inner pipe 5 , respectively, is open. Both the outer pipe 4 and the inner pipe 5 CT are fixed at only one end to the support plate 9. This relieves the mechanical stress associated with different temperatures inside the pipes from the CT structure. The design of the reactor does not matter. The shape and location of the heat exchanger may vary depending on the type of reactor (for example, two-shelf and multi-shelf).

The main volume of the reactor, limited by the reactor vessel 1, the outer pipe ST 4 and the supporting plate 9, communicates with the inner space of the inner pipe 5 using connecting pipes 3. The pipes 3 pass through the outer 4 and inner 5 pipes ST, creating channels connecting the reactor volume and inner tube 5, respectively. Here, the name “pipes” is arbitrary and implies any method of connecting the main volume of the reactor with the inner space of the inner pipe 5, which allows directing hot gas directly into the pipe 5 bypassing the annulus 13. Thus, the pipes 3 can be either separate elements or through channels. The number, size and shape of the connecting pipes 3 are optimized for a specific process.

The area of the support plate 9, limited by the annular space 13, contains through holes 12, designed to drain the cooled gases from the annular space 13.

The design contains one or more spraying devices 7, intended for supplying components (reagent or inert / slightly reactive component) into the inner tube 5 in the form of a liquid or supercritical fluid. These spraying devices can be integrated into the wall 1 of the reactor through the nozzle 10. Moreover, the spraying device 7 itself, for placing the device 7 directly in the space of the inner pipe 5, is installed through one of the pipes 3.

In one embodiment of the utility model, the structure may further comprise one or more fittings for introducing additional gaseous components (reagents or inert / slightly reactive components) into the cooled stream. For the example of FIG. 1 shows a fitting 8 for introducing gaseous reactants.

In another embodiment of the utility model, the structure may further comprise a catalyst layer 2 or and a support grid 6 designed to support the catalyst layer 2. The catalyst layer 2 may contain one or more catalysts arranged in layers or as a mixture with each other / excipients. Several separate catalyst beds may be used. This option can be implemented in the case of using ST for cooling hot reaction gases of catalytic processes (for example, in the production of oligomer-gasolines).

In yet another embodiment of the utility model, the spray device 7 is a tube, one of the ends of which is installed in the inner space of the inner pipe (5) and is equipped with a spray, and the other end is intended for installation in the reactor vessel (1).

In yet another embodiment of the utility model, the structure may further comprise a switchgear 11 for distributing a flow of chilled gas. This option can be implemented in cases where a constant gas stream concentrated in a small geometric area can harm subsequent sections of the reactor (for example, when using CT in multi-shelf reactors, a concentrated gas stream will gradually destroy the catalyst bed located below), and lead to an uneven supply of raw materials to the catalyst bed from below. As the switchgear 11, a solid plate attached to the base plate 9 with several studs / bolts or a collector plate or grill or the like can be used.

In yet another embodiment of the utility model, a venturi pipe can be used as the inner pipe 5 (the execution is shown in Fig. 5). In this case, the spray device 7 is inserted into the confuser (lower part) of the Veturi pipe. The finely dispersed mixture is released through the diffuser (upper part) of the venturi.

The proposed CT works as follows.

The gaseous reaction mixture requiring cooling ("hot gas") is discharged from the reaction zone through the support grid 6 (if any), towards the support plate 9 (Fig. 3). If necessary, additional gaseous components (reagents or inert / weakly reactive components) are introduced into the reaction mixture through the nozzle 8. Next, the gaseous reaction mixture enters the inner pipe 5 through the connecting pipes 3, bypassing the annulus 13 (Fig. 3, 4). A component (reagent or an inert / slightly reactive component) is supplied there through a spray device 7 inserted into the nozzle 10. Spraying the component is done to enhance evaporation / sublimation and homogenization of the reaction mixture. The diameter of the droplets / particles created must ensure the finely dispersed phase soars until it completely evaporates / sublimates in the reaction stream.

After entering the inner pipe 5 and mixing with the sprayed component, the cooled stream passes upward through the inner pipe 5 and then downward through the annulus 13 (Figs. 3, 4). As you move, the flow temperature decreases due to the evaporation / sublimation of fine droplets / particles of the atomized component in the gaseous stream of the reaction mixture. The amount of spray component to be supplied varies depending on the desired temperature reduction.

The cooled gas leaves the annular space 13 through the holes 12 in the support plate 9 (Fig. 3, 4). The flow of chilled gas is distributed using the switchgear 11 (if any).

Although the present utility model has been described in detail with examples of options that appear to be preferred, it must be remembered that these embodiments of the utility model are provided only to illustrate the utility model. This description should not be considered as limiting the scope of the utility model, since the design of the proposed embedded CT by specialists in the field of chemistry, chemical engineering, etc. may be amended to adapt the CT to specific materials or situations, and not beyond scope of the attached utility model formula. The person skilled in the art understands that within the scope of the utility model, which is determined by the paragraphs of the proposed formula, various options and modifications are possible, including equivalent solutions. All such variations, which are obvious to experts in the given field of technology, are considered to be included in the scope of the present utility model, which is defined in the attached formula. To clarify the present description, it should be noted that the phrase "characterized by" means "including, but not limited to."

Claims (1)

A mixing heat exchanger built into a chemical reactor containing an external pipe (4) and installed in it coaxially with the formation of the annulus (13) of the internal pipe (5), the upper part of the external pipe (4) is closed, and the upper part of the internal pipe (5) is made open, while the lower part of each of the pipes (4, 5) is mounted on a support plate (9) intended for connection with the reactor body (1), in addition, through the lower part of the outer pipe (4) and the lower part of the inner pipe (5 ) at least one connector extends a nipple (3) designed to supply a gaseous reaction mixture from the reactor volume to the space of the inner pipe (5), bypassing the annulus (13), while at least one of the nozzles (3) has a spray device (7) that provides spraying in the inner space of the inner pipe (5), the support plate (9) contains holes (12) for the exit of the cooled gas from the annular space (13).

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